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RAP1 controls rhoptry targeting of RAP2 in the malaria parasite Plasmodium falciparum
Author(s) -
Baldi Deborah L.,
Andrews Katherine T.,
Waller Ross F.,
Roos David S.,
Howard Randall F.,
Crabb Brendan S.,
Cowman Alan F.
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.11.2435
Subject(s) - rhoptry , biology , rap1 , plasmodium falciparum , microbiology and biotechnology , biogenesis , endoplasmic reticulum , malaria , immunology , gene , genetics , signal transduction , apicomplexa
Rhoptry associated protein 1 (RAP1) and 2 (RAP2), together with a poorly described third protein RAP3, form the low molecular weight complex within the rhoptries of Plasmodium falciparum . These proteins are thought to play a role in erythrocyte invasion by the extracellular merozoite and are important vaccine candidates. We used gene‐targeting technology in P.falciparum blood‐stage parasites to disrupt the RAP1 gene, producing parasites that express severely truncated forms of RAP1. Immunoprecipitation experiments suggest that truncated RAP1 species did not complex with RAP2 and RAP3. Consistent with this were the distinct subcellular localizations of RAP1 and 2 in disrupted RAP1 parasites, where RAP2 does not traffic to the rhoptries but is instead located in a compartment that appears related to the lumen of the endoplasmic reticulum. These results suggest that RAP1 is required to localize RAP2 to the rhoptries, supporting the hypothesis that rhoptry biogenesis is dependent in part on the secretory pathway in the parasite. The observation that apparently host‐protective merozoite antigens are not essential for efficient erythrocyte invasion has important implications for vaccine design.